/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.hadoop.fs.s3native;

import static org.apache.hadoop.fs.s3native.NativeS3FileSystem.PATH_DELIMITER;

import java.io.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.s3.S3Credentials;
import org.apache.hadoop.fs.s3.S3Exception;
import org.jets3t.service.S3ObjectsChunk;
import org.jets3t.service.S3Service;
import org.jets3t.service.S3ServiceException;
import org.jets3t.service.impl.rest.httpclient.RestS3Service;
import org.jets3t.service.model.S3Bucket;
import org.jets3t.service.model.S3Object;
import org.jets3t.service.security.AWSCredentials;

class Jets3tNativeFileSystemStore implements NativeFileSystemStore {

	private S3Service s3Service;
	private S3Bucket bucket;

	public void initialize(URI uri, Configuration conf) throws IOException {
		S3Credentials s3Credentials = new S3Credentials();
		s3Credentials.initialize(uri, conf);
		try {
			AWSCredentials awsCredentials = new AWSCredentials(
					s3Credentials.getAccessKey(),
					s3Credentials.getSecretAccessKey());
			this.s3Service = new RestS3Service(awsCredentials);
		} catch (S3ServiceException e) {
			handleServiceException(e);
		}
		bucket = new S3Bucket(uri.getHost());
	}

	public void storeFile(String key, File file, byte[] md5Hash)
			throws IOException {

		BufferedInputStream in = null;
		try {
			in = new BufferedInputStream(new FileInputStream(file));
			S3Object object = new S3Object(key);
			object.setDataInputStream(in);
			object.setContentType("binary/octet-stream");
			object.setContentLength(file.length());
			if (md5Hash != null) {
				object.setMd5Hash(md5Hash);
			}
			s3Service.putObject(bucket, object);
		} catch (S3ServiceException e) {
			handleServiceException(e);
		} finally {
			if (in != null) {
				try {
					in.close();
				} catch (IOException e) {
					// ignore
				}
			}
		}
	}

	public void storeEmptyFile(String key) throws IOException {
		try {
			S3Object object = new S3Object(key);
			object.setDataInputStream(new ByteArrayInputStream(new byte[0]));
			object.setContentType("binary/octet-stream");
			object.setContentLength(0);
			s3Service.putObject(bucket, object);
		} catch (S3ServiceException e) {
			handleServiceException(e);
		}
	}

	public FileMetadata retrieveMetadata(String key) throws IOException {
		try {
			S3Object object = s3Service.getObjectDetails(bucket, key);
			return new FileMetadata(key, object.getContentLength(), object
					.getLastModifiedDate().getTime());
		} catch (S3ServiceException e) {
			// Following is brittle. Is there a better way?
			if (e.getMessage().contains("ResponseCode=404")) {
				return null;
			}
			handleServiceException(e);
			return null; // never returned - keep compiler happy
		}
	}

	public InputStream retrieve(String key) throws IOException {
		try {
			S3Object object = s3Service.getObject(bucket, key);
			return object.getDataInputStream();
		} catch (S3ServiceException e) {
			handleServiceException(key, e);
			return null; // never returned - keep compiler happy
		}
	}

	public InputStream retrieve(String key, long byteRangeStart)
			throws IOException {
		try {
			S3Object object = s3Service.getObject(bucket, key, null, null,
					null, null, byteRangeStart, null);
			return object.getDataInputStream();
		} catch (S3ServiceException e) {
			handleServiceException(key, e);
			return null; // never returned - keep compiler happy
		}
	}

	public PartialListing list(String prefix, int maxListingLength)
			throws IOException {
		return list(prefix, maxListingLength, null, false);
	}

	public PartialListing list(String prefix, int maxListingLength,
			String priorLastKey, boolean recurse) throws IOException {

		return list(prefix, recurse ? null : PATH_DELIMITER, maxListingLength,
				priorLastKey);
	}

	private PartialListing list(String prefix, String delimiter,
			int maxListingLength, String priorLastKey) throws IOException {
		try {
			if (prefix.length() > 0 && !prefix.endsWith(PATH_DELIMITER)) {
				prefix += PATH_DELIMITER;
			}
			S3ObjectsChunk chunk = s3Service.listObjectsChunked(
					bucket.getName(), prefix, delimiter, maxListingLength,
					priorLastKey);

			FileMetadata[] fileMetadata = new FileMetadata[chunk.getObjects().length];
			for (int i = 0; i < fileMetadata.length; i++) {
				S3Object object = chunk.getObjects()[i];
				fileMetadata[i] = new FileMetadata(object.getKey(),
						object.getContentLength(), object.getLastModifiedDate()
								.getTime());
			}
			
			String[] commonPrefixes = chunk.getCommonPrefixes();
			
			return new PartialListing(chunk.getPriorLastKey(), fileMetadata, commonPrefixes);
		} catch (S3ServiceException e) {
			handleServiceException(e);
			return null; // never returned - keep compiler happy
		}
	}

	public void delete(String key) throws IOException {
		try {
			s3Service.deleteObject(bucket, key);
		} catch (S3ServiceException e) {
			handleServiceException(key, e);
		}
	}

	public void copy(String srcKey, String dstKey) throws IOException {
		try {
			s3Service.copyObject(bucket.getName(), srcKey, bucket.getName(),
					new S3Object(dstKey), false);
		} catch (S3ServiceException e) {
			handleServiceException(srcKey, e);
		}
	}

	public void purge(String prefix) throws IOException {
		try {
			S3Object[] objects = s3Service.listObjects(bucket, prefix, null);
			for (S3Object object : objects) {
				s3Service.deleteObject(bucket, object.getKey());
			}
		} catch (S3ServiceException e) {
			handleServiceException(e);
		}
	}

	public void dump() throws IOException {
		StringBuilder sb = new StringBuilder("S3 Native Filesystem, ");
		sb.append(bucket.getName()).append("\n");
		try {
			S3Object[] objects = s3Service.listObjects(bucket);
			for (S3Object object : objects) {
				sb.append(object.getKey()).append("\n");
			}
		} catch (S3ServiceException e) {
			handleServiceException(e);
		}
		System.out.println(sb);
	}

	private void handleServiceException(String key, S3ServiceException e)
			throws IOException {
		if ("NoSuchKey".equals(e.getS3ErrorCode())) {
			throw new FileNotFoundException("Key '" + key
					+ "' does not exist in S3");
		} else {
			handleServiceException(e);
		}
	}

	private void handleServiceException(S3ServiceException e)
			throws IOException {
		if (e.getCause() instanceof IOException) {
			throw (IOException) e.getCause();
		} else {
			throw new S3Exception(e);
		}
	}
}
